This chemical is called capsaicin, and it is found in such foods as hot peppers. It is a strong irritant that can irritate both the mucus membranes of the nose and the tear ducts of a person’s eyes. This is why oftentimes your nose can run and your eyes water while enjoying a spicy meal. Capsaicin can also dilate blood vessels, which is why people also tend to turn red in the face!
More info on why your nose runs when you eat spicy food.
Spicy food can make your nose run because of a chemical that irritates your mucus membranes.,